Research Of The Precipitation Estimation Method With Doppler Radar Reflectivity And Rainfall Auto-Gauge Data

Using of Doppler weather radar base data and rainfall auto-gauge data from Yongzhou Metrological Bureau, rainfall estimation method is researched.Exploiting the radar reflectivity data during 12-13 June 2008 and the corresponding hourly precipitation data from automatic rain gauge, Conclusions are as follows:(1) Optimization was used to get subsection optimized Z-I relationship, and subsequently used across study area to get hourly rainfall distribution.(2) Estimation precision for precipitation was greatly affected by different Z-I relationship used in radar precipitation algorithm.(3) On the basis of the above work, using the precipitation which is inversed by above several Z-I relationship as the first field, calculating the calibration factor by kalman flitter method, adjust the mean bias of the initial field. Then the accuracy of the estimation is assessed.(4) Auto rain gauge data is considered as truth。The estimated results are received by computing with kalman flitting method between different initial first fied, which are calculated by slope, root mean square error (RMSE), total rainfall, hour precipitation, deviation and relative error that are added up from single station precipitation.The results showed that:①Accuracy of estimation precipitation by kalman flitting method is higher than the one by just having Z-I relationship and results are more stable.②The kalman flitter method is the most consistent, which the first field is obtained by segment optimization method. The results explain that:the accuracy of the Initial field plays an important role in kalman flitter method.③For the 10-20mm/h rainfall intensity, the estimation effect of using kalman flitter means is the best. The reason is that:the weigh of 10-20mm/h rainfall intensity is biggest among our cases.④Analysis of the absent of the site, we find that a appropriate interpolation method is essential.⑤Error analysis of single rainfall station shows that:even at the same time, different type echoes have different value of A and b factor in Z-I equation at Yongzhou.⑥In this paper, we just have one calibration factor and don't adjusting the local deviation. To improving the effect of the inversion of precipitation, utilizing different calibration factor in different regions is a direction in the future.